Mortgage Loans Payable and Unsecured Credit Facilities (Effect of Derivative Financial Instruments on Consolidated Statements of Operations and Consolidated Statements of Equity) (Details) - USD ($) |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Designation/Cash Flow [Member] | Interest Rate Swap [Member] | |||
Derivative Instruments Gain Loss [Line Items] | |||
Net amount of Gain (loss) recognized in other comprehensive income (effective portion) | $ 2,942,000 | $ 1,162,000 | $ (4,539,000) |
Continuing Operations [Member] | |||
Derivative Instruments Gain Loss [Line Items] | |||
Net amount of (Loss) recognized in other comprehensive income reclassified into earnings (effective portion) | $ (2,345,000) | $ (3,739,000) | $ (3,621,000) |